The present invention relates to hardware implementations of sorting algorithms, and more specifically, to an efficient hardware implementation of a tournament tree sort algorithm using a hardware device having an external memory.
Sorting is generally acknowledged to be one of the most time-consuming computer-implemented procedures. It has been estimated that over twenty-five percent of all computer running time is devoted to sorting. In fact, many computing systems use over half of their available computer time for sorting. Numerous proposals and improvements have been disclosed in the art for the purposes of reducing sorting time and increasing sorting efficiency. There are a variety of sorting algorithms that are currently being used, one of which is called a tournament tree sort.
In general, a tournament tree sort is a binary-tree based selection and replacement sort algorithm. Tournament tree sort algorithms allow sorting of keys in a continuous streaming fashion. Incoming keys are entered into the leaf nodes and the keys exit, in sorted order, from the tree's root node. For a set of input records that are initially populated into the leaf nodes, pair-wise comparisons are performed at each tree level until a winning record emerges at the tree root. After the initial round of comparison and population, each non-leaf node holds exactly one input key, except the winning key which is sent out of the tree. During a continuous sort, after a winner is removed from the tree, a new input record is inserted at the previous winner's leaf node and is compared (and swapped, if needed) with exactly one non-leaf node at each level, until the tree root is reached and the new winner is determined.